1. Field of the Invention
The present invention relates to vehicle control systems capable of controlling electric-power generation state of a vehicle alternator based on a battery condition mounted to vehicles such as passenger vehicles and trucks.
2. Description of the Related Art
There is a well-known sensor failure detection device equipped with a data processing unit and a special display unit mounted to a vehicle. The data processing unit detects the occurrence of a current sensor failure and a voltage sensor failure. The current sensor detects a charging current and a discharging current of a battery. On the other hand, the voltage sensor detects the output voltage of the battery. The display unit displays the occurrence of a current sensor failure or a voltage sensor failure in order to inform the occurrence of those sensor failures to the vehicle driver and passengers. For example, Japanese patent laid open publication NO. JP 2003-68366 discloses such a conventional sensor failure detection device.
There is another well-known control device such as engine control unit (ECU) capable of controlling the generation amount of electric power of a vehicle alternator based on a battery temperature detected by a battery temperature sensor. The ECU further detects the occurrence of abnormal state of the battery temperature sensor. When detecting the occurrence of abnormal state of the battery temperature sensor, the ECU informs a vehicle driver the occurrence of abnormal state of the battery temperature sensor through a warning lamp. For example, Japanese patent laid open publication NO. JP 2007-97336 discloses such a conventional control device.
The former and latter conventional control devices described above inform to the vehicle driver or passengers the occurrence of abnormal state of the temperature sensor and the voltage sensor through the display unit or the warning lamp when the data processing unit or the ECU detects the abnormal state of each sensor.
However, those conventional devices are equipped with an additional special display unit or an additional special warning lamp in order to display the occurrence of abnormal state of each sensor. This requires an additional area of packaging an instrument panel on which the special display unit or special warning lamp is mounted. This further increases the total manufacturing cost thereof.